A channel multiplexing method for reading out a detector signal is provided, including steps: grouping L detectors to form a first source signal and a second source signal； respectively introducing L detector signals into a first signal transmission line including two readout channels A and B and a second signal transmission line including two readout channels C and D, and providing a first signal delay unit and a second signal delay unit on the first signal transmission line and the second signal transmission line； and symbolizing source detectors for forming signals according to pulses of the four readout channels A, B, C and D, and obtaining final pulse information.
